Hepatitis C virus inhibitors

ABSTRACT

Hepatitis C virus inhibitors having the general formula 
                         
are disclosed. Compositions comprising the compounds and methods for using the compounds to inhibit HCV are also disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application Ser. No. 61/100,896 filed Sep. 29, 2008.

The present disclosure is generally directed to antiviral compounds, and more specifically directed to compounds which inhibit the function of the NS3 protease (also referred to herein as “serine protease”) encoded by Hepatitis C virus (HCV), compositions comprising such compounds, and methods for inhibiting the function of the NS3 protease.

HCV is a major human pathogen, infecting an estimated 170 million persons worldwide—roughly five times the number infected by human immunodeficiency virus type 1. A substantial fraction of these HCV infected individuals develop serious progressive liver disease, including cirrhosis and hepatocellular carcinoma.

Presently, the most effective HCV therapy employs a combination of alpha-interferon and ribavirin, leading to sustained efficacy in 40% of patients. Recent clinical results demonstrate that pegylated alpha-interferon is superior to unmodified alpha-interferon as monotherapy. However, even with experimental therapeutic regimens involving combinations of pegylated alpha-interferon and ribavirin, a substantial fraction of patients do not have a sustained reduction in viral load. Thus, there is a clear and unmet need to develop effective therapeutics for treatment of HCV infection.

HCV is a positive-stranded RNA virus. Based on a comparison of the deduced amino acid sequence and the extensive similarity in the 5′ untranslated region, HCV has been classified as a separate genus in the Flaviviridae family. All members of the Flaviviridae family have enveloped virions that contain a positive stranded RNA genome encoding all known virus-specific proteins via translation of a single, uninterrupted, open reading frame.

Considerable heterogeneity is found within the nucleotide and encoded amino acid sequence throughout the HCV genome. Six major genotypes have been characterized, and more than 50 subtypes have been described. The major genotypes of HCV differ in their distribution worldwide, and the clinical significance of the genetic heterogeneity of HCV remains elusive despite numerous studies of the possible effect of genotypes on pathogenesis and therapy.

The single strand HCV RNA genome is approximately 9500 nucleotides in length and has a single open reading frame (ORF) encoding a single large polyprotein of about 3000 amino acids. In infected cells, this polyprotein is cleaved at multiple sites by cellular and viral proteases to produce the structural and non-structural (NS) proteins. In the case of HCV, the generation of mature non-structural proteins (NS2, NS3, NS4A, NS4B, NS5A, and NS5B) is effected by two viral proteases. The first one cleaves at the NS2-NS3 junction; the second one is a serine protease contained within the N-terminal region of NS3 and mediates all the subsequent cleavages downstream of NS3, both in cis, at the NS3-NS4A cleavage site, and in trans, for the remaining NS4A-NS4B, NS4B-NS5A, NS5A-NS5B sites. The NS4A protein appears to serve multiple functions, acting as a co-factor for the NS3 protease and possibly assisting in the membrane localization of NS3 and other viral replicase components. The complex formation of the NS3 protein with NS4A is essential for efficient polyprotein processing, enhancing the proteolytic cleavage at all of the sites. The NS3 protein also exhibits nucleoside triphosphatase and RNA helicase activities. NS5B is a RNA-dependent RNA polymerase that is involved in the replication of HCV.

The present disclosure provides peptide compounds that can inhibit the functioning of the NS3 protease, e.g., in combination with the NS4A protease. Further, the present disclosure describes the administration of combination therapy to a patient whereby a compound in accordance with the present disclosure, which is effective to inhibit the HCV NS3 protease, can be administered with additional compounds having anti-HCV activity.

In its first aspect the present disclosure provides a compound of formula (I)

or a pharmaceutically acceptable salt thereof, wherein

R¹ is selected from hydroxy and —NHSO₂R⁵;

R² is selected from hydrogen, alkenyl, alkyl, and cycloalkyl, wherein the alkenyl, the alkyl, and the cycloalkyl are each optionally substituted with one, two, three, or four halo groups;

R³ is a phenyl group substituted with an additional phenyl or a heterocyclyl wherein the additional phenyl and the heterocyclyl can be further optionally substituted with one, two, three, four, or five substituents independently selected from alkoxy, alkyl, cyano, halo, haloalkoxy, haloalkyl, and hydroxy;

R⁴ is selected from hydrogen, alkoxycarbonyl, alkyl, alkylcarbonyl, alkylsulfonyl, cycloalkyloxycarbonyl, haloalkoxycarbonyl, haloalkyl, haloalkylcarbonyl, haloalkylsulfonyl, (NR^(a)R^(b))carbonyl, and (NR^(a)R^(b))sulfonyl, wherein the cycloalkyl part of the cycloalkyloxycarbonyl is optionally substituted with one, two, or three haloalkyl groups;

R⁵ is selected from alkyl, aryl, arylalkyl, cycloalkyl, (cycloalkyl)alkyl, heterocyclyl, and NR^(a)R^(b); wherein the alkyl and cycloalkyl are each optionally substituted with one group selected from alkyl, alkoxy, halo, haloalkyl, cyano, cyanoalkyl, and haloalkoxy;

R^(a) and R^(b) are independently selected from hydrogen, alkoxy, alkyl, aryl, arylalkyl, cycloalkyl, (cycloalkyl)alkyl, haloalkyl, heterocyclyl, and heterocyclylalkyl;

X is selected from O, S, SO, and SO₂; and

Q is a C₅₋₉ saturated or unsaturated chain optionally substituted with one or two groups independently selected from alkyl, and halo.

In a first embodiment of the first aspect the present disclosure provides a compound of formula (I), or a pharmaceutically acceptable salt thereof, wherein R¹ is —NHSO₂R⁵. In a second embodiment of the first aspect X is S. In a third embodiment of the first aspect Q is a C₇₋₉ saturated or unsaturated unsubstituted chain. In a fourth embodiment of the first aspect R³ is a phenyl group substituted with an unsubstituted phenyl group. In a fifth embodiment of the first aspect R² is alkenyl. In a sixth embodiment of the first aspect R⁴ is alkoxycarbonyl.

In a seventh embodiment of the first aspect the present disclosure provides a compound of formula (I), or a pharmaceutically acceptable salt thereof, wherein

R¹ is —NHSO₂R⁵;

R² is alkenyl; and

R⁴ is alkoxycarbonyl.

In an eighthembodiment of the first aspect the present disclosure provides a compound of formula (I), or a pharmaceutically acceptable salt thereof, wherein

R¹ is —NHSO₂R⁵; wherein R⁵ is cycloalkyl;

R² is alkenyl;

R³ is a phenyl group substituted with an unsubstituted phenyl group;

R⁴ is alkoxycarbonyl;

X is S; and

Q is a C₇₋₉ saturated or unsaturated unsubstituted chain.

In a second aspect the present disclosure provides a composition comprising the compound of Formula (I), or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier. In a first embodiment of the second aspect the composition further comprises at least one additional compound having anti-HCV activity. In a second embodiment of the second aspect at least one of the additional compounds is an interferon or a ribavirin. In a third embodiment of the second aspect the interferon is selected from interferon alpha 2B, pegylated interferon alpha, consensus interferon, interferon alpha 2A, and lymphoblastiod interferon tau.

In a fourth embodiment of the second aspect the present disclosure provides a composition comprising the compound of Formula (I), or a pharmaceutically acceptable salt thereof, a pharmaceutically acceptable carrier, and at least one additional compound having anti-HCV activity, wherein at least one of the additional compounds is selected from interleukin 2, interleukin 6, interleukin 12, a compound that enhances the development of a type 1 helper T cell response, interfering RNA, anti-sense RNA, 1 ml Imiqimod, ribavirin, an inosine 5′-monophospate dehydrogenase inhibitor, amantadine, and rimantadine.

In a fifth embodiment of the second aspect the present disclosure provides a composition comprising the compound of Formula (I), or a pharmaceutically acceptable salt thereof, a pharmaceutically acceptable carrier, and at least one additional compound having anti-HCV activity, wherein at least one of the additional compounds is effective to inhibit the function of a target selected from HCV metalloprotease, HCV serine protease, HCV polymerase, HCV helicase, HCV NS4B protein, HCV entry, HCV assembly, HCV egress, HCV NS5A protein, and IMPDH for the treatment of an HCV infection.

In a third aspect the present disclosure provides a composition comprising a compound of Formula (I), or a pharmaceutically acceptable salt thereof, one, two, three, four, or five additional compounds having anti-HCV activity, and a pharmaceutically acceptable carrier. In a first embodiment of the third aspect the composition comprises three or four additional compounds having anti-HCV activity. In a second embodiment of the third aspect the composition comprises one or two additional compounds having anti-HCV activity.

In a fourth aspect the present disclosure provides a method of treating an HCV infection in a patient, comprising administering to the patient a therapeutically effective amount of Formula (I), or a pharmaceutically acceptable salt thereof. In a first embodiment of the fourth aspect the method further comprises administering at least one additional compound having anti-HCV activity prior to, after, or simultaneously with the compound of Formula (I), or a pharmaceutically acceptable salt thereof. In a second embodiment of the fourth aspect at least one of the additional compounds is an interferon or a ribavirin. In a third embodiment of the fourth aspect the interferon is selected from interferon alpha 2B, pegylated interferon alpha, consensus interferon, interferon alpha 2A, and lymphoblastiod interferon tau.

In a fourth embodiment of the fourth aspect the present disclosure provides a method of treating an HCV infection in a patient, comprising administering to the patient a therapeutically effective amount of Formula (I), or a pharmaceutically acceptable salt thereof, and at least one additional compound having anti-HCV activity prior to, after, or simultaneously with the compound of Formula (I), or a pharmaceutically acceptable salt thereof, wherein at least one of the additional compounds is selected from interleukin 2, interleukin 6, interleukin 12, a compound that enhances the development of a type 1 helper T cell response, interfering RNA, anti-sense RNA, 1 ml Imiqimod, ribavirin, an inosine 5′-monophospate dehydrogenase inhibitor, amantadine, and rimantadine.

In a fifth embodiment of the fourth aspect the present disclosure provides a method of treating an HCV infection in a patient, comprising administering to the patient a therapeutically effective amount of Formula (I), or a pharmaceutically acceptable salt thereof, and at least one additional compound having anti-HCV activity prior to, after, or simultaneously with the compound of Formula (I), or a pharmaceutically acceptable salt thereof, wherein at least one of the additional compounds is effective to inhibit the function of a target selected from HCV metalloprotease, HCV serine protease, HCV polymerase, HCV helicase, HCV NS4B protein, HCV entry, HCV assembly, HCV egress, HCV NS5A protein, and IMPDH for the treatment of an HCV infection.

In a fifth aspect the present disclosure provides a method of treating an HCV infection in a patient, comprising administering to the patient a therapeutically effective amount of a compound of formula (I), or a pharmaceutically acceptable salt thereof and one, two, three, four, or five additional compounds having anti-HCV activity prior to, after, or simultaneously with the compound of formula (I), or a pharmaceutically acceptable salt thereof. In a first embodiment of the fifth aspect the method comprises administering three or four additional compounds having anti-HCV activity. In a second embodiment of the fifth aspect the method comprises administering one or two additional compounds having anti-HCV activity.

Other aspects of the present disclosure may include suitable combinations of embodiments disclosed herein.

Yet other aspects and embodiments may be found in the description provided herein.

The description of the present disclosure herein should be construed in congruity with the laws and principals of chemical bonding. In some instances it may be necessary to remove a hydrogen atom in order to accommodate a substitutent at any given location.

It should be understood that the compounds encompassed by the present disclosure are those that are suitably stable for use as pharmaceutical agent.

It is intended that the definition of any substituent or variable at a particular location in a molecule be independent of its definitions elsewhere in that molecule. For example, when n is 2, each of the two R⁴ groups may be the same or different.

All patents, patent applications, and literature references cited in the specification are herein incorporated by reference in their entirety. In the case of inconsistencies, the present disclosure, including definitions, will prevail.

As used herein, the singular forms “a”, “an”, and “the” include plural reference unless the context clearly dictates otherwise.

The term “alkenyl,” as used herein, refers to a straight or branched chain group of two to six carbon atoms containing at least one carbon-carbon double bond.

The term “alkoxy,” as used herein, refers to an alkyl group attached to the parent molecular moiety through an oxygen atom.

The term “alkoxycarbonyl,” as used herein, refers to an alkoxy group attached to the parent molecular moiety through a carbonyl group.

The term “alkyl,” as used herein, refers to a group derived from a straight or branched chain saturated hydrocarbon containing from one to six carbon atoms.

The term “alkylcarbonyl,” as used herein, refers to an alkyl group attached to the parent molecular moiety through a carbonyl group.

The term “alkylsulfonyl,” as used herein, refers to an alkyl group attached to the parent molecular moiety through a sulfonyl group.

The term “aryl,” as used herein, refers to a phenyl group, or a bicyclic fused ring system wherein one or both of the rings is a phenyl group. Bicyclic fused ring systems consist of a phenyl group fused to a four- to six-membered aromatic or non-aromatic carbocyclic ring. The aryl groups of the present invention can be attached to the parent molecular moiety through any substitutable carbon atom in the group. Representative examples of aryl groups include, but are not limited to, indenyl, indenyl, naphthyl, phenyl, and tetrahydronaphthyl.

The term “arylalkyl,” as used herein, refers to an alkyl group substituted with one, two, or three aryl groups.

The term “cyano,” as used herein, refers to —CN.

The term “cyanoalkyl,” as used herein, refers to an alkyl group substituted with one, two, or three cyano groups.

The term “cycloalkyl,” as used herein, refers to a saturated monocyclic or bicyclic hydrocarbon ring system having three to seven carbon atoms and zero heteroatoms. Representative examples of cycloalkyl groups include, but are not limited to, cyclopropyl, cyclobutyl, and cyclopentyl.

The term “(cycloalkyl)alkyl,” as used herein, refers to an alkyl group substituted with one, two, or three cycloalkyl groups.

The term “cycloalkyloxy,” as used herein, refers to a cycloalkyl group attached to the parent molecular moiety through an oxygen atom.

The term “cycloalkyloxycarbonyl,” as used herein, refers to a cycloalkyloxy group attached to the parent molecular moiety through a carbonyl group.

The terms “halo” and “halogen,” as used herein, refer to F, Cl, Br, and I.

The term “haloalkoxy,” as used herein, refers to a haloalkyl group attached to the parent molecular moiety through an oxygen atom.

The term “haloalkoxycarbonyl,” as used herein, refers to a haloalkoxy group attached to the parent molecular moiety through a carbonyl group.

The term “haloalkyl,” as used herein, refers to an alkyl group substituted with one, two, three, or four halogen atoms.

The term “haloalkylsulfonyl,” as used herein, refers to a haloalkyl group attached to the parent molecular moiety through a sulfonyl group.

The term “heterocyclyl,” as used herein, refers to a five-, six-, or seven-membered ring containing one, two, or three heteroatoms independently selected from nitrogen, oxygen, and sulfur. The five-membered ring has zero to two double bonds and the six- and seven-membered rings have zero to three double bonds. The term “heterocyclyl” also includes bicyclic groups in which the heterocyclyl ring is fused to a phenyl group, a monocyclic cycloalkenyl group, a monocyclic cycloalkyl group, or another monocyclic heterocyclyl group; and tricyclic groups in which a bicyclic system is fused to a phenyl group, a monocyclic cycloalkenyl group, a monocyclic cycloalkyl group, or another monocyclic heterocyclyl group. The heterocyclyl groups of the present invention can be attached to the parent molecular moiety through a carbon atom or a nitrogen atom in the group. Examples of heterocyclyl groups include, but are not limited to, benzothienyl, furyl, imidazolyl, indolinyl, indolyl, isothiazolyl, isoxazolyl, morpholinyl, oxazolyl, piperazinyl, piperidinyl, pyrazolyl, pyridinyl, pyrrolidinyl, pyrrolopyridinyl, pyrrolyl, thiazolyl, thienyl, and thiomorpholinyl.

The term “heterocyclylalkyl,” as used herein, refers to an alkyl group substituted with one, two, or three heterocyclyl groups.

The term “hydroxy,” as used herein, refers to —OH.

The term “—NR^(a)R^(b),” as used herein, refers to two groups, R^(a) and R^(b), which are attached to the parent molecular moiety through a nitrogen atom. R^(a) and R^(b) are independently selected from hydrogen, alkoxy, alkyl, aryl, arylalkyl, cycloalkyl, (cycloalkyl)alkyl, haloalkyl, heterocyclyl, and heterocyclylalkyl.

The term “(NR^(a)R^(b))carbonyl,” as used herein, refers to an —NR^(a)R^(b) group attached to the parent molecular moiety through a carbonyl group.

The term “(NR^(a)R^(b))sulfonyl,” as used herein, refers to an —NR^(a)R^(b) group attached to the parent molecular moiety through a sulfonyl group.

The term “sulfonyl,” as used herein, refers to —SO₂.

The compounds of the present disclosure can exist as pharmaceutically acceptable salts. The term “pharmaceutically acceptable salt,” as used herein, represents salts or zwitterionic forms of the compounds of the present disclosure which are water or oil-soluble or dispersible, which are, within the scope of sound medical judgment, suitable for use in contact with the tissues of patients without excessive toxicity, irritation, allergic response, or other problem or complication commensurate with a reasonable benefit/risk ratio, and are effective for their intended use. The salts can be prepared during the final isolation and purification of the compounds or separately by reacting a suitable basic functionality with a suitable acid. Representative acid addition salts include acetate, adipate, alginate, citrate, aspartate, benzoate, benzenesulfonate, bisulfate, butyrate, camphorate, camphorsulfonate; digluconate, glycerophosphate, hemisulfate, heptanoate, hexanoate, formate, fumarate, hydrochloride, hydrobromide, hydroiodide, 2-hydroxyethanesulfonate, lactate, maleate, mesitylenesulfonate, methanesulfonate, naphthylenesulfonate, nicotinate, 2-naphthalenesulfonate, oxalate, palmoate, pectinate, persulfate, 3-phenylproprionate, picrate, pivalate, propionate, succinate, tartrate, trichloroacetate, trifluoroacetate, phosphate, glutamate, bicarbonate, para-toluenesulfonate, and undecanoate. Examples of acids which can be employed to form pharmaceutically acceptable addition salts include inorganic acids such as hydrochloric, hydrobromic, sulfuric, and phosphoric, and organic acids such as oxalic, maleic, succinic, and citric.

Basic addition salts can be prepared during the final isolation and purification of the compounds by reacting an acidic group with a suitable base such as the hydroxide, carbonate, or bicarbonate of a metal cation or with ammonia or an organic primary, secondary, or tertiary amine. The cations of pharmaceutically acceptable salts include lithium, sodium, potassium, calcium, magnesium, and aluminum, as well as nontoxic quaternary amine cations such as ammonium, tetramethylammonium, tetraethylammonium, methylamine, dimethylamine, trimethylamine, triethylamine, diethylamine, ethylamine, tributylamine, pyridine, N,N-dimethylaniline, N-methylpiperidine, N-methylmorpholine, dicyclohexylamine, procaine, dibenzylamine, N,N-dibenzylphenethylamine, and N,N′-dibenzylethylenediamine. Other representative organic amines useful for the formation of base addition salts include ethylenediamine, ethanolamine, diethanolamine, piperidine, and piperazine.

As used herein, the term “anti-HCV activity” means the compound is effective to treat the HCV virus.

The term “compounds of the disclosure”, and equivalent expressions, are meant to embrace compounds of formula (I), and pharmaceutically acceptable enantiomers, diastereomers, and salts thereof. Similarly, references to intermediates, are meant to embrace their salts where the context so permits.

The term “patient” includes both human and other mammals.

The term “pharmaceutical composition” means a composition comprising a compound of the disclosure in combination with at least one additional pharmaceutical carrier, i.e., adjuvant, excipient or vehicle, such as diluents, preserving agents, fillers, flow regulating agents, disintegrating agents, wetting agents, emulsifying agents, suspending agents, sweetening agents, flavoring agents, perfuming agents, antibacterial agents, antifungal agents, lubricating agents and dispensing agents, depending on the nature of the mode of administration and dosage forms. Ingredients listed in Remington's Pharmaceutical Sciences, 18^(th) ed., Mack Publishing Company, Easton, Pa. (1999) for example, may be used.

The phrase “pharmaceutically acceptable” is employed herein to refer to those compounds, materials, compositions, and/or dosage forms which are, within the scope of sound medical judgment, suitable for use in contact with the tissues of patients without excessive toxicity, irritation, allergic response, or other problem or complication commensurate with a reasonable risk/benefit ratio.

The term “therapeutically effective amount” means the total amount of each active component that is sufficient to show a meaningful patient benefit, e.g., a sustained reduction in viral load. When applied to an individual active ingredient, administered alone, the term refers to that ingredient alone. When applied to a combination, the term refers to combined amounts of the active ingredients that result in the therapeutic effect, whether administered in combination, serially or simultaneously.

The terms “treat” and “treating” refers to: (i) preventing a disease, disorder or condition from occurring in a patient which may be predisposed to the disease, disorder and/or condition but has not yet been diagnosed as having it; (ii) inhibiting the disease, disorder or condition, i.e., arresting its development; and/or (iii) relieving the disease, disorder or condition, i.e., causing regression of the disease, disorder and/or condition.

Where used in naming compounds of the present disclosure, the designations P1′, P1, P2, P2*, P3, and P4, as used herein, map the relative positions of the amino acid residues of a protease inhibitor binding relative to the binding of the natural peptide cleavage substrate. Cleavage occurs in the natural substrate between P1 and P1′ where the nonprime positions designate amino acids starting from the C-terminus end of the peptide natural cleavage site extending towards the N-terminus; whereas, the prime positions emanate from the N-terminus end of the cleavage site designation and extend toward the C-terminus. For example, P1′ refers to the first position away from the right hand end of the C-terminus of the cleavage site (i.e. N-terminus first position); whereas P1 starts the numbering from the left hand side of the C-terminus cleavage site, P2: second position from the C-terminus, etc.). (see Berger A. & Schechter I., Transactions of the Royal Society London series (1970), B257, 249-264].

Asymmetric centers exist in the compounds of the present disclosure. For example, the compounds may include P1 cyclopropyl element of formula

wherein C₁ and C₂ each represent an asymmetric carbon atom at positions 1 and 2 of the cyclopropyl ring.

It should be understood that the disclosure encompasses all stereochemical forms, or mixtures thereof, which possess the ability to inhibit HCV protease.

Certain compounds of the present disclosure may also exist in different stable conformational forms which may be separable. Torsional asymmetry due to restricted rotation about an asymmetric single bond, for example because of steric hindrance or ring strain, may permit separation of different conformers. The present disclosure includes each conformational isomer of these compounds and mixtures thereof.

Certain compounds of the present disclosure may exist in zwitterionic form and the present disclosure includes each zwitterionic form of these compounds and mixtures thereof.

When it is possible that, for use in therapy, therapeutically effective amounts of a compound of formula (I), as well as pharmaceutically acceptable salts thereof, may be administered as the raw chemical, it is possible to present the active ingredient as a pharmaceutical composition. Accordingly, the disclosure further provides pharmaceutical compositions, which include therapeutically effective amounts of compounds of formula (I) or pharmaceutically acceptable salts thereof, and one or more pharmaceutically acceptable carriers, diluents, or excipients. The compounds of formula (I) and pharmaceutically acceptable salts thereof, are as described above. The carrier(s), diluent(s), or excipient(s) must be acceptable in the sense of being compatible with the other ingredients of the formulation and not deleterious to the recipient thereof. In accordance with another aspect of the disclosure there is also provided a process for the preparation of a pharmaceutical formulation including admixing a compound of formula (I), or a pharmaceutically acceptable salt thereof, with one or more pharmaceutically acceptable carriers, diluents, or excipients.

Pharmaceutical formulations may be presented in unit dose forms containing a predetermined amount of active ingredient per unit dose. Dosage levels of between about 0.01 and about 150 milligram per kilogram (“mg/kg”) body weight per day, preferably between about 0.05 and about 100 mg/kg body weight per day of the compounds of the disclosure are typical in a monotherapy for the prevention and treatment of HCV mediated disease. Typically, the pharmaceutical compositions of this disclosure will be administered from about 1 to about 5 times per day or alternatively, as a continuous infusion. Such administration can be used as a chronic or acute therapy. The amount of active ingredient that may be combined with the carrier materials to produce a single dosage form will vary depending on the condition being treated, the severity of the condition, the time of administration, the route of administration, the rate of excretion of the compound employed, the duration of treatment, and the age, gender, weight, and condition of the patient. Preferred unit dosage formulations are those containing a daily dose or sub-dose, as herein above recited, or an appropriate fraction thereof, of an active ingredient. Generally, treatment is initiated with small dosages substantially less than the optimum dose of the compound. Thereafter, the dosage is increased by small increments until the optimum effect under the circumstances is reached. In general, the compound is most desirably administered at a concentration level that will generally afford antivirally effective results without causing any harmful or deleterious side effects.

When the compositions of this disclosure comprise a combination of a compound of the disclosure and one or more additional therapeutic and/or prophylactic agent, both the compound and the additional agent can be present in a dose that is less than or equal to the dosage normally administered in a monotherapy regimen. The compositions of this disclosure may be co-formulated with one or more additional therapeutic or prophylactic agents, for example, in the form of a monolithic and/or bi/multi-layer tablet or may be administered separately from the therapeutic or prophylactic agent(s).

Pharmaceutical formulations may be adapted for administration by any appropriate route, for example by the oral (including buccal or sublingual), rectal, nasal, topical (including buccal, sublingual, or transdermal), vaginal, or parenteral (including subcutaneous, intracutaneous, intramuscular, intra-articular, intrasynovial, intrasternal, intrathecal, intralesional, intravenous, or intradermal injections or infusions) route. Such formulations may be prepared by any method known in the art of pharmacy, for example by bringing into association the active ingredient with the carrier(s) or excipient(s).

Pharmaceutical formulations adapted for oral administration may be presented as discrete units such as capsules or tablets; powders or granules; solutions or suspensions in aqueous or non-aqueous liquids; edible foams or whips; or oil-in-water liquid emulsions or water-in-oil emulsions.

For instance, for oral administration in the form of a tablet or capsule, the active drug component can be combined with an oral, non-toxic pharmaceutically acceptable inert carrier such as ethanol, glycerol, water, and the like. Powders are prepared by comminuting the compound to a suitable fine size and mixing with a similarly comminuted pharmaceutical carrier such as an edible carbohydrate, as, for example, starch or mannitol. Flavoring, preservative, dispersing, and coloring agent can also be present.

Capsules are made by preparing a powder mixture, as described above, and filling formed gelatin sheaths. Glidants and lubricants such as colloidal silica, talc, magnesium stearate, calcium stearate, or solid polyethylene glycol can be added to the powder mixture before the filling operation. A disintegrating or solubilizing agent such as agar-agar, calcium carbonate, or sodium carbonate can also be added to improve the availability of the medicament when the capsule is ingested.

Moreover, when desired or necessary, suitable binders, lubricants, disintegrating agents, and coloring agents can also be incorporated into the mixture. Suitable binders include starch, gelatin, natural sugars such as glucose or beta-lactose, corn sweeteners, natural and synthetic gums such as acacia, tragacanth or sodium alginate, carboxymethylcellulose, polyethylene glycol, and the like. Lubricants used in these dosage forms include sodium oleate, sodium chloride, and the like. Disintegrators include, without limitation, starch, methyl cellulose, agar, betonite, xanthan gum, and the like. Tablets are formulated, for example, by preparing a powder mixture, granulating or slugging, adding a lubricant and disintegrant, and pressing into tablets. A powder mixture is prepared by mixing the compound, suitable comminuted, with a diluent or base as described above, and optionally, with a binder such as carboxymethylcellulose, an aliginate, gelating, or polyvinyl pyrrolidone, a solution retardant such as paraffin, a resorption accelerator such as a quaternary salt and/or and absorption agent such as betonite, kaolin, or dicalcium phosphate. The powder mixture can be granulated by wetting with a binder such as syrup, starch paste, acadia mucilage, or solutions of cellulosic or polymeric materials and forcing through a screen. As an alternative to granulating, the powder mixture can be run through the tablet machine and the result is imperfectly formed slugs broken into granules. The granules can be lubricated to prevent sticking to the tablet forming dies by means of the addition of stearic acid, a stearate salt, talc; or mineral oil. The lubricated mixture is then compressed into tablets. The compounds of the present disclosure can also be combined with a free flowing inert carrier and compressed into tablets directly without going through the granulating or slugging steps. A clear or opaque protective coating consisting of a sealing coat of shellac, a coating of sugar or polymeric material, and a polish coating of wax can be provided. Dyestuffs can be added to these coatings to distinguish different unit dosages.

Oral fluids such as solution, syrups, and elixirs can be prepared in dosage unit form so that a given quantity contains a predetermined amount of the compound. Syrups can be prepared by dissolving the compound in a suitably flavored aqueous solution, while elixirs are prepared through the use of a non-toxic vehicle. Solubilizers and emulsifiers such as ethoxylated isostearyl alcohols and polyoxyethylene sorbitol ethers, preservatives, flavor additive such as peppermint oil or natural sweeteners, or saccharin or other artificial sweeteners, and the like can also be added.

Where appropriate, dosage unit formulations for oral administration can be microencapsulated. The formulation can also be prepared to prolong or sustain the release as for example by coating or embedding particulate material in polymers, wax, or the like.

The compounds of formula (I), and pharmaceutically acceptable salts thereof, can also be administered in the form of liposome delivery systems, such as small unilamellar vesicles, large unilamellar vesicles, and multilamellar vesicles. Liposomes can be formed from a variety of phopholipids, such as cholesterol, stearylamine, or phophatidylcholines.

The compounds of formula (I) and pharmaceutically acceptable salts thereof may also be delivered by the use of monoclonal antibodies as individual carriers to which the compound molecules are coupled. The compounds may also be coupled with soluble polymers as targetable drug carriers. Such polymers can include polyvinylpyrrolidone, pyran copolymer, polyhydroxypropylmethacrylamidephenol, polyhydroxyethylaspartamidephenol, or polyethyleneoxidepolylysine substituted with palitoyl residues. Furthermore, the compounds may be coupled to a class of biodegradable polymers useful in achieving controlled release of a drug, for example, polylactic acid, polepsilon caprolactone, polyhydroxy butyric acid, polyorthoesters, polyacetals, polydihydropyrans, polycyanoacrylates, and cross-linked or amphipathic block copolymers of hydrogels.

Pharmaceutical formulations adapted for transdermal administration may be presented as discrete patches intended to remain in intimate contact with the epidermis of the recipient for a prolonged period of time. For example, the active ingredient may be delivered from the patch by iontophoresis as generally described in Pharmaceutical Research, 3(6), 318 (1986).

Pharmaceutical formulations adapted for topical administration may be formulated as ointments, creams, suspensions, lotions, powders, solutions, pastes, gels, sprays, aerosols, or oils.

For treatments of the eye or other external tissues, for example mouth and skin, the formulations are preferably applied as a topical ointment or cream. When formulated in an ointment, the active ingredient may be employed with either a paraffinic or a water-miscible ointment base. Alternatively, the active ingredient may be formulated in a cream with an oil-in-water cream base or a water-in oil base.

Pharmaceutical formulations adapted for topical administrations to the eye include eye drops wherein the active ingredient is dissolved or suspended in a suitable carrier, especially an aqueous solvent.

Pharmaceutical formulations adapted for topical administration in the mouth include lozenges, pastilles, and mouth washes.

Pharmaceutical formulations adapted for rectal administration may be presented as suppositories or as enemas.

Pharmaceutical formulations adapted for nasal administration wherein the carrier is a solid include a course powder which is administered in the manner in which snuff is taken, i.e., by rapid inhalation through the nasal passage from a container of the powder held close up to the nose. Suitable formulations wherein the carrier is a liquid, for administration as a nasal spray or nasal drops, include aqueous or oil solutions of the active ingredient.

Pharmaceutical formulations adapted for administration by inhalation include fine particle dusts or mists, which may be generated by means of various types of metered, dose pressurized aerosols, nebulizers, or insufflators.

Pharmaceutical formulations adapted for vaginal administration may be presented as pessaries, tampons, creams, gels, pastes, foams, or spray formulations.

Pharmaceutical formulations adapted for parenteral administration include aqueous and non-aqueous sterile injection solutions which may contain anti-oxidants, buffers, bacteriostats, and soutes which render the formulation isotonic with the blood of the intended recipient; and aqueous and non-aqueous sterile suspensions which may include suspending agents and thickening agents. The formulations may be presented in unit-dose or multi-dose containers, for example sealed ampoules and vials, and may be stored in a freeze-dried (lyophilized) condition requiring only the addition of the sterile liquid carrier, for example water for injections, immediately prior to use. Extemporaneous injection solutions and suspensions may be prepared from sterile powders, granules, and tablets.

It should be understood that in addition to the ingredients particularly mentioned above, the formulations may include other agents conventional in the art having regard to the type of formulation in question, for example those suitable for oral administration may include flavoring agents.

Table 1 below lists some illustrative examples of compounds that can be administered with the compounds of this disclosure. The compounds of the disclosure can be administered with other anti-HCV activity compounds in combination therapy, either jointly or separately, or by combining the compounds into a composition.

TABLE 1 Type of Inhibitor or Brand Name Physiological Class Target Source Company NIM811 Cyclophilin Inhibitor Novartis Zadaxin Immunomodulator Sciclone Suvus Methylene blue Bioenvision Actilon (CPG10101) TLR9 agonist Coley Batabulin (T67) Anticancer β-tubulin inhibitor Tularik Inc., South San Francisco, CA ISIS 14803 Antiviral antisense ISIS Pharmaceuticals Inc, Carlsbad, CA/Elan Phamaceuticals Inc., New York, NY Summetrel Antiviral antiviral Endo Pharmaceuticals Holdings Inc., Chadds Ford, PA GS-9132 (ACH-806) Antiviral HCV Inhibitor Achillion/ Gilead Pyrazolopyrimidine Antiviral HCV Inhibitors Arrow compounds and salts Therapeutics Ltd. From WO-2005047288 26 May 2005 Levovirin Antiviral IMPDH inhibitor Ribapharm Inc., Costa Mesa, CA Merimepodib Antiviral IMPDH inhibitor Vertex (VX-497) Pharmaceuticals Inc., Cambridge, MA XTL-6865 (XTL-002) Antiviral monoclonal antibody XTL Biopharmaceuticals Ltd., Rehovot, Isreal Telaprevir Antiviral NS3 serine protease Vertex (VX-950, LY-570310) inhibitor Pharmaceuticals Inc., Cambridge, MA/Eli Lilly and Co. Inc., Indianapolis, IN HCV-796 Antiviral NS5B Replicase Wyeth/ Inhibitor Viropharma NM-283 Antiviral NS5B Replicase Idenix/Novartis Inhibitor GL-59728 Antiviral NS5B Replicase Gene Labs/ Inhibitor Novartis GL-60667 Antiviral NS5B Replicase Gene Labs/ Inhibitor Novartis 2′C MeA Antiviral NS5B Replicase Gilead Inhibitor PSI 6130 Antiviral NS5B Replicase Roche Inhibitor R1626 Antiviral NS5B Replicase Roche Inhibitor 2′C Methyl adenosine Antiviral NS5B Replicase Merck Inhibitor JTK-003 Antiviral RdRp inhibitor Japan Tobacco Inc., Tokyo, Japan Levovirin Antiviral ribavirin ICN Pharmaceuticals, Costa Mesa, CA Ribavirin Antiviral ribavirin Schering-Plough Corporation, Kenilworth, NJ Viramidine Antiviral Ribavirin Prodrug Ribapharm Inc., Costa Mesa, CA Heptazyme Antiviral ribozyme Ribozyme Pharmaceuticals Inc., Boulder, CO BILN-2061 Antiviral serine protease Boehringer inhibitor Ingelheim Pharma KG, Ingelheim, Germany SCH 503034 Antiviral serine protease Schering Plough inhibitor Zadazim Immune modulator Immune modulator SciClone Pharmaceuticals Inc., San Mateo, CA Ceplene Immunomodulator immune modulator Maxim Pharmaceuticals Inc., San Diego, CA CellCept Immunosuppressant HCV IgG F. Hoffmann-La immunosuppressant Roche LTD, Basel, Switzerland Civacir Immunosuppressant HCV IgG Nabi immunosuppressant Biopharmaceuticals Inc., Boca Raton, FL Albuferon-α Interferon albumin IFN-α2b Human Genome Sciences Inc., Rockville, MD Infergen A Interferon IFN alfacon-1 InterMune Pharmaceuticals Inc., Brisbane, CA Omega IFN Interferon IFN-ω Intarcia Therapeutics IFN-β and EMZ701 Interferon IFN-β and EMZ701 Transition Therapeutics Inc., Ontario, Canada Rebif Interferon IFN-β1a Serono, Geneva, Switzerland Roferon A Interferon IFN-α2a F. Hoffmann-La Roche LTD, Basel, Switzerland Intron A Interferon IFN-α2b Schering-Plough Corporation, Kenilworth, NJ Intron A and Zadaxin Interferon IFN-α2b/α1-thymosin RegeneRx Biopharmiceuticals Inc., Bethesda, MD/ SciClone Pharmaceuticals Inc, San Mateo, CA Rebetron Interferon IFN-α2b/ribavirin Schering-Plough Corporation, Kenilworth, NJ Actimmune Interferon INF-γ InterMune Inc., Brisbane, CA Interferon-β Interferon Interferon-β-1a Serono Multiferon Interferon Long lasting IFN Viragen/Valentis Wellferon Interferon lymphoblastoid IFN- GlaxoSmithKline αn1 plc, Uxbridge, UK Omniferon Interferon natural IFN-α Viragen Inc., Plantation, FL Pegasys Interferon PEGylated IFN-α2a F. Hoffmann-La Roche LTD, Basel, Switzerland Pegasys and Ceplene Interferon PEGylated IFN-α2a/ Maxim immune modulator Pharmaceuticals Inc., San Diego, CA Pegasys and Ribavirin Interferon PEGylated IFN- F. Hoffmann-La α2A/ribavirin Roche LTD, Basel, Switzerland PEG-Intron Interferon PEGylated IFN-α2b Schering-Plough Corporation, Kenilworth, NJ PEG-Intron/Ribavirin Interferon PEGylated IFN- Schering-Plough α2b/ribavirin Corporation, Kenilworth, NJ IP-501 Liver protection antifibrotic Indevus Pharmaceuticals Inc., Lexington, MA IDN-6556 Liver protection caspase inhibitor Idun Pharmaceuticals Inc., San Diego, CA ITMN-191 (R-7227) Antiviral serine protease InterMune inhibitor Pharmaceuticals Inc., Brisbane, CA GL-59728 Antiviral NS5B Replicase Genelabs Inhibitor ANA-971 Antiviral TLR-7 agonist Anadys MK 78009 Antiviral serine protease Merck inhibitor TMC-435350 Antiviral serine protease Tibotec inhibitor

The compounds of the disclosure may also be used as laboratory reagents. Compounds may be instrumental in providing research tools for designing of viral replication assays, validation of animal assay systems and structural biology studies to further enhance knowledge of the HCV disease mechanisms. Further, the compounds of the present disclosure are useful in establishing or determining the binding site of other antiviral compounds, for example, by competitive inhibition.

The compounds of this disclosure may also be used to treat or prevent viral contamination of materials and therefore reduce the risk of viral infection of laboratory or medical personnel or patients who come in contact with such materials, e.g., blood, tissue, surgical instruments and garments, laboratory instruments and garments, and blood collection or transfusion apparatuses and materials.

This disclosure is intended to encompass compounds having formula (I) when prepared by synthetic processes or by metabolic processes including those occurring in the human or animal body (in vivo) or processes occurring in vitro.

The present disclosure will now be described in connection with certain embodiments which are not intended to limit its scope. On the contrary, the present disclosure covers all alternatives, modifications, and equivalents as can be included within the scope of the claims. Thus, the following examples, which include specific embodiments, will illustrate one practice of the present disclosure, it being understood that the examples are for the purposes of illustration of certain embodiments and are presented to provide what is believed to be the most useful and readily understood description of its procedures and conceptual aspects.

The abbreviations used in the present application, including particularly in the illustrative schemes and examples which follow, are well-known to those skilled in the art. Some of the abbreviations used are as follows: Ar for aryl; PG for protecting group; OTf for trifluoroacetate; TMS for trimethylsilyl; MeOD for CD₃OD; HATU for O-(7-azabenzotriazol-1-yl)-N,N,N′,N′-tetramethyluronium phosphate; THF for tetrahydrofuran; and TFA for trifluoroacetic acid.

The starting materials useful to synthesize the compounds of the present disclosure are known to those skilled in the art and can be readily manufactured or are commercially available.

The following methods set forth below are provided for illustrative purposes and are not intended to limit the scope of the claims. It will be recognized that it may be necessary to prepare such a compound in which a functional group is protected using a conventional protecting group then to remove the protecting group to provide a compound of the present disclosure. The details concerning the use of protecting groups in accordance with the present disclosure are known to those skilled in the art.

EXAMPLES

General Description of Synthesis

The compounds of the present invention may be synthesized as outlined in the generic Scheme 1, and 2.

Example 1 Compound 1

Step 1.

To a clear solution of (2S,4R)-1-benzyl 2-methyl 4-(biphenyl-4-yl)-4-hydroxypyrrolidine-1,2-dicarboxylate (3236 mg, 7.5 mmol) and prop-2-ene-1-thiol (834 mg, 9.00 mmol) in Acetonitrile (40 mL) was added Scandium(III) trifluoromethanesulfonate (369 mg, 0.750 mmol) as solid by one portion at room temperature. The formed pink solution was stirred at this temperature for 20 h. Quenched with sat. ammonium chloride, extracted with EtOAc. Washed the organic layer with brine, dried over MgSO4, filtered, evaporated in vacuo. The residue was purified by Biotage column, eluted with 5%˜50% EtOAc-Hexane to afford a mixture of diastereomers (2.88 g, 79%) and recovered starting material (0.600 g, 18%). This mixture was purified by Biotage column again, eluted with 2%˜8% EtOAc-Toluene to afford the desired product (2S,4R)-1-benzyl 2-methyl 4-(allylthio)-4-(biphenyl-4-yl)pyrrolidine-1,2-dicarboxylate (900 mg, 1.661 mmol, 22.15% yield) as an viscous oil and the undesired diastereomer plus some overlapped fraction (1.80 g) as an viscous oil. ¹H NMR (500 MHz, CHLOROFORM-D) δ ppm 2.59-2.75 (m, 1 H), 2.77-2.93 (m, 3 H), 3.60 (s, 1.5 H), 3.77 (s, 1.5 H), 3.92 (d, J=11.60 Hz, 1 H), 4.20-4.30 (m, 1 H), 4.37-4.47 (m, 1 H), 4.92-5.34 (m, 4 H), 5.55-5.72 (m, 1 H), 7.20-7.65 (m, 14 H). LC-MS (retention time: 3.34 min, method B), MS m/z 488 (M+H).

Step 2.

To an iced solution of (2S,4R)-1-benzyl 2-methyl 4-(allylthio)-4-(biphenyl-4-yl)pyrrolidine-1,2-dicarboxylate (810 mg, 1.661 mmol) in Acetonitrile (8 mL) was added Iodotrimethylsilane (0.355 mL, 2.492 mmol). The formed light brown solution was stirred at room temperature for 2 h. Cooled with ice bath, quenched with MeOH. The formed light brown, solution was purified by prep-HPLC, and the collected fractions were evaporated on speed-vac system. The yellow residue was triturated with 1M HCl in ether, filtered, dried in vacuo to afford the desired product (2S,4R)-methyl 4-(allylthio)-4-(biphenyl-4-yl)pyrrolidine-2-carboxylate, HCl (497 mg, 1.275 mmol, 77% yield) as a yellow foam. ¹H NMR (500 MHz, MeOD) δ ppm 2.93-3.08 (m, 3 H), 3.09-3.19 (m, 1 H), 3.80-3.87 (m, 1 H), 3.95 (s, 3 H), 4.04 (d, J=12.21 Hz, 1 H), 4.73-4.79 (m, 1 H), 5.02 (d, J=9.77 Hz, 1 H), 5.09 (dd, J=16.94, 1.37 Hz, 1 H), 5.57-5.70 (m, 1 H), 7.34-7.43 (m, 1 H), 7.42-7.57 (m, 4 H), 7.62-7.68 (m, 2 H), 7.68-7.76 (m, 2 H). LC-MS (retention time: 2.43 min, method. B), MS m/z 354 (M+H).

Step 3.

To an iced slurry of (2S,4R)-methyl 4-(allylthio)-4-(biphenyl-4-yl)pyrrolidine-2-carboxylate, HCl (97 mg, 0.25 mmol), (S)-2-(tert-butoxycarbonylamino)non-8-enoic acid (81 mg, 0.300 mmol), and HATU (143 mg, 0.375 mmol) in DCM (4 mL) was added N,N-Diisopropylethylamine (0.218 mL, 1.250 mmol). The formed colorless slurry was stirred at room temperature overnight. Diluted with DCM, washed with 5% citric acid. The organic layer was washed with 0.1 M NaOH and brine, dried over MgSO₄, filtered, evaporated in vacuo. The residue was purified by Biotage column, eluted with 5-35% EtOAc-Hexane to yield the desired product (2S,4R)-methyl 4-(allylthio)-4-(biphenyl-4-yl)-1-((S)-2-(tert-butoxycarbonylamino)non-8-enoyl)pyrrolidine-2-carboxylate (130 mg, 0.193 mmol, 77% yield) as a white wax. ¹H NMR (500 MHz, MeOD) δ ppm 1.28-1.59 (m, 17 H), 1.60-1.71 (m, 1 H), 1.74-1.84 (m, 1 H), 2.08-2.18 (m, 2 H), 2.58-2.68 (m, 1 H), 2.84-3.03 (m, 3 H), 3.69-3.78 (m, 3 H), 4.02-4.14 (m, 1 H), 4.34-4.49 (m, 2 H), 4.69-4.78 (m, 1 H), 4.91-5.11 (m, 4 H), 5.64-5.76 (m, 1 H), 5.80-5.94 (m, 1 H), 7.36 (q, J=7.12 Hz, 1 H), 7.45 (q, J=7.83 Hz, 2 H), 7.56-7.71 (m, 6 H). LC-MS (retention time: 3.56 min, method C), MS m/z 607 (M+H).

Step 4.

A solution of (2S,4R)-methyl 4-(allylthio)-4-(biphenyl-4-yl)-1-((S)-2-(tert-butoxycarbonylamino)non-8-enoyl)pyrrolidine-2-carboxylate (123 mg, 0.203 mmol) in Dichloromethane (50 mL) was purged with nitrogen for 30 min. And then Hoveyda-Grubbs Catalyst 2nd Generation (153 mg, 0.243 mmol) was added. The resulting green solution was heated to reflux for 5 h. The reaction was quenched with 2-Mercaptonicotinic acid (62.9 mg, 0.405 mmol) and washed with sat. Na₂CO₃, and brine. Dried over MgSO₄, filtered, concentrated in vacuo. The brown residue was purified by Biotage column, eluted with gradient 5%˜40% EtOAc-Hexane to afford the desired product (3S,13R,15S,E)-methyl 13-(biphenyl-4-yl)-3-(tert-butoxycarbonylamino)-2-oxo-12-thia-1-azabicyclo[11.2.1]hexadec-9-ene-15-carboxylate (93 mg, 0.145 mmol, 71.3% yield) as an off-white solid. NMR analysis showed the configuration of the double bond is exclusively trans. ¹H NMR (500 MHz, MeOD) δ ppm 1.39-1.55 (m, 13 H), 1.55-1.75 (m, 4 H), 1.81-1.92 (m, 1 H), 1.97-2.08 (m, 1 H), 2.20-2.31 (m, 1 H), 2.57 (dd, J=12.82, 7.93 Hz, 1 H), 2.76-2.85 (m, 1 H), 2.92 (dd, J=15.87, 7.93 Hz, 1 H, 3.68-3.80 (m, 3 H), 4.20 (t, J=7.78 Hz, 1 H), 4.31-4.40 (m, 1 H), 4.52-4.65 (m, 2 H), 5.65 (dd, J=14.19, 6.87 Hz, 1 H), 5.85 (dd, J=14.95, 7.32 Hz, 1 H), 7.36 (t, J=7.32 Hz, 1 H), 7.41-7.50 (m, 2 H), 7.58-7.74 (m, 6 H). LC-MS (retention time: 3.42 min, method C), MS m/z 579 (M+H).

Step 5.

To a solution of (3S,13R,15S,E)-methyl 13-(biphenyl-4-yl)-3-(tert-butoxycarbonylamino)-2-oxo-12-thia-1-azabicyclo[11.2.1]hexadec-9-ene-15-carboxylate (90 mg, 0.156 mmol) in THF (1 mL) and MeOH (1.000 mL) was added pre-made solution of lithium hydroxide hydrate (19.58 mg, 0.467 mmol) in Water (1 mL). The resulting cloudy solution was stirred at room for 5 h. Quenched with 5% citric acid, extracted with EtOAc. The organic layer was washed with brine, dried over MgSO₄, filtered, evaporated, to afford the desired product (3S,13R,15S,E)-13-(biphenyl-4-yl)-3-(tert-butoxycarbonylamino)-2-oxo-12-thia-1-azabicyclo[11.2.1]hexadec-9-ene-15-carboxylic acid (84 mg, 0.134 mmol, 86% yield) as an off-white foam. LC-MS (retention time: 3.32 min, method C), MS m/z 565 (M+H).

Step 6.

To an iced slurry of (3S,13R,15S,Z)-13-(biphenyl-4-yl)-3-(tert-butoxycarbonylamino)-2-oxo-12-thia-1-azabicyclo[11.2.1]hexadec-9-ene-15-carboxylic acid (28 mg, 0.050 mmol), (1R,2S)-1-amino-N-(cyclopropylsulfonyl)-2-vinylcyclopropanecarboxamide, pTSA, 0.68H₂O (25.7 mg, 0.062 mmol), and HATU (28.5 mg, 0.075 mmol) in DCM (1 mL) was added N,N-Diisopropylethylamine (0.043 mL, 0.248 mmol). The formed light brown solution was stirred at room temperature overnight. Diluted with EtOAc, washed it with 5% citric acid, and brine, dried over MgSO4, filtered, evaporated. The formed residue was purified by prep-HPLC to afford the desired product tert-butyl (3S,13R,15S,E)-13-(biphenyl-4-yl)-15-((1R,2S)-1-(cyclopropylsulfonylcarbamoyl)-2-vinylcyclopropylcarbamoyl)-2-oxo-12-thia-1-azabicyclo[11.2.1]hexadec-9-en-3-ylcarbamate (22 mg, 0.026 mmol, 52.5% yield) as a white solid.

¹H NMR (500 MHz, MeOD) δ ppm 1.08-1.10 (m, 2 H), 1.18-1.20 (m, 1 H), 1.25-1.31 (m, 1 H), 1.38-1.45 (m, 3 H), 1.50-1.52 (m, 12 H), 1.53-1.75 (m, 4 H), 1.84-2.05 (m, 3 H), 2.21 (d, J=8.55 Hz, 1 H), 2.29 (d, J=6.10 Hz, 1 H), 2.53-2.61 (m, 1 H), 2.63-2.73 (m, 1 H), 2.88-3.00 (m, 2 H), 3.88 (dd, J=10.22, 6.26 Hz, 1 H), 4.33 (d, J=10.99 Hz, 1 H), 4.57-4.70 (m, 2 H), 5.12 (d, J=10.68 Hz, 1 H), 5.30 (d, J=17.40 Hz, 1 H), 5.60-5.68 (m, 1 H), 5.68-5.81 (m, 1 H), 5.84-5.97 (m, 1 H), 7.37 (t, J=7.32 Hz, 1 H), 7.46 (t, J=7.63 Hz, 2 H), 7.63 (dd, J=13.73, 7.93 Hz, 4 H), 7.74 (d, J=8.24 Hz, 2 H). LC-MS (retention time: 3.38 min, method C), MS m/z 778 (M+H).

Example 2 Compound 2

Step 1.

To an iced slurry of (2S,4R)-methyl 4-(allylthio)-4-(biphenyl-4-yl)pyrrolidine-2-carboxylate, HCl (97 mg, 0.25 mmol), (S)-2-(tert-butoxycarbonylamino)dec-9-enoic acid (86 mg, 0.300 mmol), and HATU (143 mg, 0.375 mmol) in DCM (4 mL) was added N,N-Diisopropylethylamine (0.218 mL, 1.250 mmol). The formed colorless slurry was stirred at room temperature overnight. Diluted with DCM, washed with 5% citric acid. The organic layer was washed with 0.1 M NaOH and brine, dried over MgSO₄, filtered, evaporated in vacuo. The residue was purified by Biotage column, eluted with 1˜25% EtOAc-Hexane to yield the desired product (2S,4R)-methyl 4-(allylthio)-4-(biphenyl-4-yl)-1-((S)-2-(tert-butoxycarbonylamino)dec-9-enoyl)pyrrolidine-2-carboxylate (111 mg, 0.161 mmol, 64.4% yield) as a white wax. LC-MS (retention time: 3.68 min, method C), MS m/z 621 (M+H).

Step 2.

A solution of (2S,4R)-methyl 4-(allylthio)-4-(biphenyl-4-yl)-1-((S)-2-(tert-butoxycarbonylamino)dec-9-enoyl)pyrrolidine-2-carboxylate (108 mg, 0.174 mmol) in Dichloromethane (50 mL) was purged with nitrogen for 30 min. And then Hoveyda-Grubbs Catalyst 2nd Generation (131 mg, 0.209 mmol) was added. The resulting green solution was heated to reflux for 5 h. The reaction was quenched with 2-Mercaptonicotinic acid (54.0 mg, 0.348 mmol) and washed with sat. Na2CO3, and brine. Dried over MgSO₄, filtered, concentrated in vacuo. The brown residue was purified by Biotage column, eluted with gradient 5%˜40% EtOAc-Hexane to afford the desired product (3S,14R,16S,E)-methyl 14-(biphenyl-4-yl)-3-(tert-butoxycarbonylamino)-2-oxo-13-thia-1-azabicyclo[12.2.1]heptadec-10-ene-16-carboxylate (86 mg, 0.131 mmol, 75% yield) as an off-white solid.

LC-MS (retention time: 3.52 min, method C), MS m/z 593 (M+

Step 3.

To a solution of (3S,14R,16S,E)-methyl 14-(biphenyl-4-yl)-3-(tert-butoxycarbonylamino)-2-oxo-13-thia-1-azabicyclo[12.2.1]heptadec-10-ene-16-carboxylate (82 mg, 0.138 mmol) in THF (1 mL) and MeOH (1.000 mL) was added pre-made solution of lithium hydroxide hydrate (17.41 mg, 0.415 mmol) in Water (1 mL). The resulting cloudy solution was stirred at room for 5 h. Quenched with 5% citric acid, extracted with EtOAc. The organic layer was washed with brine, dried over MgSO4, filtered, evaporated, to afford the desired product (3S,14R,16S,E)-14-(biphenyl-4-yl)-3-(tert-butoxycarbonylamino)-2-oxo-13-thia-1-azabicyclo[12.2.1]heptadec-10-ene-16-carboxylic acid (80 mg, 0.124 mmol, 90% yield) as a tan foam. LC-MS (retention time: 3.43 min, method C), MS m/z 579 (M+H).

Step 4.

To an iced slurry of (3S,14R,16S,E)-14-(biphenyl-4-yl)-3-(tert-butoxycarbonylamino)-2-oxo-13-thia-1-azabicyclo[12.2.1]heptadec-10-ene-16-carboxylic acid, (1R,2S)-1-amino-N-(cyclopropylsulfonyl)-2-vinylcyclopropanecarboxamide, pTSA, 0.68H₂O (29.6 mg, 0.071 mmol), and HATU (32.5 mg, 0.0855 mmol) in DCM (2 mL) was added N,N-Diisopropylethylamine (0.050 mL, 0.285 mmol). The formed light brown solution was stirred at room temperature overnight. Diluted with EtOAc, washed it with 5% citric acid, and brine, dried over MgSO4, filtered, evaporated. The formed residue was purified by Biotage column, eluted with gradient 5%˜40% Acetone-Hexane to afford the desired product tert-butyl (3S,14R,16S,E)-14-(biphenyl-4-yl)-16-((1R,2S)-1-(cyclopropylsulfonylcarbamoyl)-2-vinylcyclopropylcarbamoyl)-2-oxo-13-thia-1-azabicyclo[12.2.1]heptadec-10-en-3-ylcarbamate (31 mg, 0.038 mmol, 66.0% yield) as a white foam. ¹H NMR (500 MHz, MeOD) δ ppm 1.09 (s, 1 H) 1.16-1.32 (m, 3 H) 1.33-1.40 (m, 2 H) 1.41-1.63 (m, 16 H) 1.64-1.83 (m, 4 H) 1.87-1.99 (m, 2 H) 2.00-2.11 (m, 1 H) 2.13-2.24 (m, 1 H) 2.24-2.34 (m, 1 H) 2.40 (t, J=11.29 Hz, 1 H) 2.62-2.75 (m, 2 H) 2.87-3.01 (m, 1 H) 3.08 (d, J=14.95 Hz, 1 H) 3.87 (dd, J=10.38, 6.41 Hz, 1 H) 4.01 (d, J=10.68 Hz, 1 H) 4.59-4.80 (m, 2 H) 5.12 (d, J=10.07 Hz, 1 H) 5.29 (d, J=17.09 Hz, 1 H) 5.53-5.63 (m, 2 H) 5.64-5.80 (m, 1 H) 7.37 (t, J=7.48 Hz, 1 H) 7.47 (t, J=7.48 Hz, 2 H) 7.57-7.64 (m, 2 H), 7.68-7.82 (m, 4 H). LC-MS (retention time: 3.48 min, method C), MS ink 792 (M+H), 735 (M-t-Bu), 691 (M-BOC).

Example 3 Compound 3

Step 1.

A vessel containing (3S,14R,16S,E)-14-(biphenyl-4-yl)-3-(tert-butoxycarbonylamino)-2-oxo-13-thia-1-azabicyclo[12.2.1]heptadec-10-ene-16-carboxylic acid (46 mg, 0.079 mmol), Platinum (372 mg, 0.095 mmol) 5% on carbon, sulfided, and Methanol (4 mL) was placed on Parr shaker under H₂ atmosphere with 30 psi overnight. Quenched with celite, filtered, washed with excessive MeOH, DCM and EtOAc. The combined filtrate was evaporated to dryness. The white residue (20 mg) was used for the next, coupling reaction without further purification. LC-MS (retention time: 3.43 min, method C), MS m/z 581 (M+H).

Step 2.

To an iced slurry of (3S,14R,16S)-14-(biphenyl-4-yl)-3-(tert-butoxycarbonylamino)-2-oxo-13-thia-1-azabicyclo[12.2.1]heptadecane-16-carboxylic acid (20 mg, 0.034 mmol), (1R,2S)-1-amino-N-(cyclopropylsulfonyl)-2-vinylcyclopropanecarboxamide, pTSA, 0.68H₂O (17.85 mg, 0.043 mmol), and HATU (32.5 mg, 0.0855 mmol) in DCM (1 mL) was added N,N-Diisopropylethylamine (0.030 mL, 0.172 mmol). The formed light brown solution was stirred at room temperature overnight. Diluted with EtOAc, washed it with 5% citric acid, and brine, dried over MgSO4, filtered, evaporated. The formed residue was purified by prep-HPLC to afford the desired product tert-butyl (3S,14R,16S)-14-(biphenyl-4-yl)-16-((1R,2S)-1-(cyclopropylsulfonylcarbamoyl)-2-vinylcyclopropylcarbamoyl)-2-oxo-13-thia-1-azabicyclo[12.2.1]heptadecan-3-ylcarbamate (7 mg, 8.65 mmol, 25.1% A yield) as a white foam. ¹H NMR (400 MHz, MeOD) δ ppm 0.94-1.37 (m, 13 H) 1.35-1.63 (m, 12 H) 1.84 (dd, J=8.16, 5.40 Hz, 1 H) 1.91-2.08 (m, 4 H) 2.08-2.19 (m, 1 H) 2.19-2.45 (m, 4 H) 2.59 (dd, J=12.30, 6.53 Hz, 1 H) 2.82-2.99 (m, 1 H) 3.87 (dd, J=10.29, 6.53 Hz, 1 H) 4.00-4.22 (m, 2 H) 4.64 (t, J=8.53 Hz, 1 H) 5.07 (dd, J=10.29, 1.51 Hz, 1 H) 5.24 (dd, J=17.19, 1.38 Hz, 1 H) 5.60-5.78 (m, 1 H) 6.36 (d, J=8.53 Hz, 1 H) 7.32 (t, J=7.28 Hz, 1 H) 7.42 (t, J=7.53 Hz, 2 H) 7.53-7.74 (m, 6 H); LC-MS (retention time: 3.50 min, method C), MS m/z 793.5 (M+H), 737 (M-t-Bu), 693 (M-BOC).

Example 4 Compound 4

Step 1.

To an iced slurry of (2S,4R)-methyl 4-(allylthio)-4-(biphenyl-4-yl)pyrrolidine-2-carboxylate, HCl (110 mg, 0.282 mmol), (S)-2-(tert-butoxycarbonylamino)oct-7-enoic acid (87 mg, 0.339 mmol), and HATU (143 mg, 0.375 mmol) in DCM (4 mL) was added N,N-Diisopropylethylamine (0.246 mL, 1.410 mmol). The formed colorless slurry was stirred at room temperature overnight. Diluted with DCM, washed with 5% citric acid and brine. Dried over MgSO4, filtered, evaporated. The residue was purified by Biotage column, eluted with 5˜30% EtOAc-Hexane to yield the desired product (2S,4R)-methyl 4-(allylthio)-4-(biphenyl-4-yl)-1-((S)-2-(tert-butoxycarbonylamino)oct-7-enoyl)pyrrolidine-2-carboxylate (123 mg, 0.187 mmol, 66.2% yield) as a white solid.

LC-MS (retention time: 3.45 min, method C), MS m/z 593 (M+H).

Step 2.

A solution of (2S,4R)-methyl 4-(allylthio)-4-(biphenyl-4-yl)-1-((S)-2-(tert-butoxycarbonylamino)oct-7-enoyl)pyrrolidine-2-carboxylate (120 mg, 0.202 mmol) in Dichloromethane (50 mL) was purged with nitrogen for 30 min. And then Hoveyda-Grubbs Catalyst 2nd Generation (153 mg, 0.243 mmol) was added. The resulting green solution was heated to reflux for 5 h. The reaction was quenched with 2-Mercaptonicotinic acid (62.8 mg, 0.405 mmol) and washed with sat. Na₂CO₃, and brine. Dried over MgSO₄, filtered, concentrated in vacuo. The brown residue was purified by Biotage column, eluted with gradient 5%˜50% EtOAc-Hexane to afford the desired product (3S,12R,14S,E)-methyl 12-(biphenyl-4-yl)-3-(tert-butoxycarbonylamino)-2-oxo-11-thia-1-azabicyclo[10.2.1]pentadec-8-ene-14-carboxylate (94 mg, 0.150 mmol, 74.0% yield) as grenish foam.

LC-MS (retention time: 3.22 min, method C), MS m/z 565 (M+H).

Step 3.

To a solution of (3S,12R,14S,E)-methyl 12-(biphenyl-4-yl)-3-(tert-butoxycarbonylamino)-2-oxo-11-thia-1-azabicyclo[10.2.1]pentadec-8-ene-14-carboxylate (90 mg, 0.159 mmol) in THF (1 mL) and MeOH (1.000 mL) was added pre-made solution of lithium hydroxide hydrate (20.06 mg, 0.478 mmol) in Water (1 mL). The resulting cloudy solution was stirred at room for 15 h. LS/MS showed the reaction was only half way done. Another portion of lithium hydroxide hydrate (20.06 mg, 0.478 mmol) was added, and stirred for additional 20 h. Quenched with 5% citric acid, extracted with EtOAc. The organic layer was washed with brine, dried over MgSO4, filtered, evaporated, to afford the desired product (3S,12R,14S,E)-12-(biphenyl-4-yl)-3-(tert-butoxycarbonylamino)-2-oxo-11-thia-1-azabicyclo[10.2.1]pentadec-8-ene-14-carboxylic acid (72 mg, 0.118 mmol, 73.8% yield) as a white foam. LC-MS (retention time: 3.10 min, method C), MS m/z 551 (M+H).

Step 4.

To an iced slurry of (3S,12R,14S,E)-12-(biphenyl-4-yl)-3-(tert-butoxycarbonylamino)-2-oxo-11-thia-1-azabicyclo[10.2.1]pentadec-8-ene-14-carboxylic acid (70 mg, 0.127 mmol), (1R,2S)-1-amino-N-(cyclopropylsulfonyl)-2-vinylcyclopropanecarboxamide, pTSA, 0.68H₂O (65.9 mg, 0.159 mmol), and HATU (72.2 mg, 0.190 mmol) in DCM (4 mL) was added N,N-Diisopropylethylamine (0.111 mL, 0.636 mmol). The formed light brown solution was stirred at room temperature overnight. Diluted with EtOAc, washed it with 5% citric acid, and brine, dried over MgSO₄, filtered, evaporated. The formed residue was purified by Biotage column, eluted with gradient 5%˜40% Acetone-Hexane to afford 59 mg of white solid. The product purified by Biotage silica gel column was subjected to prep-HPLC conditions (Sunfire column, 50%˜100% B, MeOH/TFA/water, 20 min gradient time, 30 min stop) to afford the desired product tert-butyl (3S,12R,14S,E)-12-(biphenyl-4-yl)-14-((1R,2S)-1-(cyclopropylsulfonylcarbamoyl)-2-vinylcyclopropylcarbamoyl)-2-oxo-11-thia-1-azabicyclo[10.2.1]pentadec-8-en-3-ylcarbamate as the second fraction. ¹H NMR (500 MHz, MeOD) δ ppm 1.00-1.36 (m, 4 H) 1.37-1.57 (m, 12 H) 1.58-1.68 (m, 1 H) 1.73 (d, J=6.41 Hz, 2 H) 1.92 (dd, J=8.09, 5.34 Hz, 1 H) 1.96-2.06 (m, 1 H) 2.07-2.17 (m, 1 H) 2.23-2.40 (m, 2 H) 2.62 (dd, J=13.28, 7.78 Hz, 1 H) 2.92 (dd, J=13.12, 6.41 Hz, 1 H) 2.95-3.04 (m, 1 H) 3.09 (dd, J=15.11, 6.56 Hz, 1 H) 3.41-3.55 (m, 1 H) 4.31 (t, J=6.87 Hz, 1 H) 4.40 (dd, J=8.85, 4.88 Hz, 1 H) 4.47 (d, J=10.68 Hz, 1 H) 4.90-5.01 (m, 1 H) 5.15 (d, J=11.29 Hz, 1 H) 5.33 (d, J=17.09 Hz, 1 H) 5.63-5.74 (m, 1 H) 5.74-5.86 (m, 1 H) 5.93-6.07 (m, 1 H) 7.37 (t, J=7.32 Hz, 1 H) 7.47 (t, J=7.63 Hz, 2 H) 7.56-7.76 (m, 6 H). LC-MS (retention time: 3.24 min, method C), MS m/z 763 (M+H), 707 (M-t-Bu), 663 (M-BOC).

LC/MS conditions for Method B.

Start % B=0

Final % B=100

Gradient Time=3 min

Stop Time=4 min

Flow Rate=4 ml/min

Wavelength=220

Solvent A=90% Water-10% Methanol-0.1% TFA

Solvent B=10% Water-90% Methanol-0.1% TFA Column 3=(3) PHENOMENEX-LUNA 4.6×50 mm S10

LC/MS conditions for Method C.

Start % B=30

Final % B=100

Gradient Time=3 min

Stop Time=4 min

Flow Rate=4 ml/min

Wavelength=220

Solvent A=90% Water-10% Methanol-0.1% TFA

Solvent B=10% Water-90% Methanol-0.1% TFA

Column 3=(3) PHENOMENEX-LUNA 4.6×50 mm S10

Biological Studies

HCV NS3/4A protease complex enzyme assays and cell-based HCV replicon assays were utilized in the present disclosure, and were prepared, conducted and validated as follows:

Generation of Recombinant HCV NS3/4A Protease Complex

HCV NS3 protease complexes, derived from the BMS strain, H77 strain or J4L6S strain, were generated, as described below. These purified recombinant proteins were generated for use in a homogeneous assay (see below) to provide an indication of how effective compounds of the present disclosure would be in inhibiting HCV NS3 proteolytic activity.

Serum from an HCV-infected patient was obtained from Dr. T. Wright, San Francisco Hospital. An engineered full-length cDNA (compliment deoxyribonucleic acid) template of the HCV genome (BMS strain) was constructed from DNA fragments obtained by reverse transcription-PCR (RT-PCR) of serum RNA (ribonucleic acid) and using primers selected on the basis of homology between other genotype 1a strains. From the determination of the entire genome sequence, a genotype 1a was assigned to the HCV isolate according to the classification of Simmonds et al. (See P Simmonds, K A Rose, S Graham, S W Chan, F McOmish, B C Dow, E A Follett, P L Yap and H Marsden, J. Clin. Microbiol., 31(6), 1493-1503 (1993)). The amino acid sequence of the nonstructural region, NS2-5B, was shown to be >97% identical to HCV genotype 1a (H77) and 87% identical to genotype 1b (J4L6S). The infectious clones, H77 (1a genotype) and J4L6S (1b genotype) were obtained from R. Purcell (NIH) and the sequences are published in Genbank (AAB67036, see Yanagi, M., Purcell, R. H., Emerson, S. U. and Bukh, J. Proc. Natl. Acad. Sci. U.S.A. 94(16), 8738-8743 (1997); AF054247, see Yanagi, M., St Claire, M., Shapiro, M., Emerson, S. U., Purcell, R. H. and Bukh, J., Virology 244 (1), 161-172. (1998)).

The H77 and J4L6S strains were used for production of recombinant NS3/4A protease complexes. DNA encoding the recombinant HCV NS3/4A protease complex (amino acids 1027 to 1711) for these strains was manipulated as described by P. Gallinari et al. (see Gallinari P, Paolini C, Brennan D, Nardi C, Steinkuhler C, De Francesco R. Biochemistry. 38(17):5620-32, (1999)). Briefly, a three-lysine solubilizing tail was added at the 3′-end of the NS4A coding region. The cysteine in the P1 position of the NS4A-NS4B cleavage site (amino acid 1711) was changed to a glycine to avoid the proteolytic cleavage of the lysine tag. Furthermore, a cysteine to serine mutation was introduced by PCR at amino acid position 1454 to prevent the autolytic cleavage in the NS3 helicase domain. The variant DNA fragment was cloned in the pET21b bacterial expression vector (Novagen) and the NS3/4A complex was expressed in Escherichia coli strain BL21 (DE3) (Invitrogen) following the protocol described by P. Gallinari et al. (see Gallinari P, Brennan D, Nardi C, Brunetti M, Tomei L, Steinkuhler C, De Francesco R., J Viral. 72(8):6758-69 (1998)) with modifications. Briefly, the NS3/4A protease complex expression was induced with 0.5 millimolar (mM) Isopropyl β-D-1-thiogalactopyranoside (IPTG) for 22 hours (h) at 20° C. A typical fermentation (1 Liter (L)) yielded approximately 10 grams (g) of wet cell paste. The cells were resuspended in lysis buffer (10 mL/g) consisting of 25 mM N-(2-Hydroxyethyl)piperazine-N′-(2-Ethane Sulfonic acid) (HEPES), pH 7.5, 20% glycerol, 500 mM Sodium Chloride (NaCl), 0.5% Triton X-100, 1 microgram/milliliter (“μg/mL”) lysozyme, 5 mM Magnesium Chloride (MgCl₂), 1 μg/ml DnaseI, 5 mM β-Mercaptoethanol (βME), Protease inhibitor-Ethylenediamine Tetraacetic acid (EDTA) free (Roche), homogenized and incubated for 20 minutes (min) at 4° C. The homogenate was sonicated and clarified by ultra-centrifugation at 235000 g for 1 hour (h) at 4° C. Imidazole was added to the supernatant to a final concentration of 15 mM and the pH adjusted to 8.0. The crude protein extract was loaded on a Nickel-Nitrilotriacetic acid (Ni-NTA) column pre-equilibrated with buffer B (25 mM HEPES, pH 8.0, 20% glycerol, 500 mM NaCl, 0.5% Triton X-100, 15 mM imidazole, 5 mM βME). The sample was loaded at a flow rate of 1 mL/min. The column was washed with 15 column volumes of buffer C (same as buffer B except with 0.2% Triton X-100). The protein was eluted with 5 column volumes of buffer D (same as buffer C except with 200 mM Imidazole).

NS3/4A protease complex-containing fractions were pooled and loaded on a desalting column Superdex-S200 pre-equilibrated with buffer D (25 mM HEPES, pH 7.5, 20% glycerol, 300 mM NaCl, 0.2% Triton X-100, 10 mM βME). Sample was loaded at a flow rate of 1 mL/min. NS3/4A protease complex-containing fractions were pooled and concentrated to approximately 0.5 mg/ml. The purity of the NS3/4A protease complexes, derived from the BMS, H77 and J4L6S strains, were judged to be greater than 90% by SDS-PAGE and mass spectrometry analyses. The enzyme was stored at −80° C., thawed on ice and diluted prior to use in assay buffer.

FRET Peptide Assay to Monitor HCV NS3/4A Proteolytic Activity

The purpose of this in vitro assay was to measure the inhibition of HCV NS3 protease complexes, derived from the BMS strain, H77 strain or J4L6S strain, as described above, by compounds of the present disclosure. This assay provides an indication of how effective compounds of the present disclosure would be in inhibiting HCV NS3 proteolytic activity.

In order to monitor HCV NS3/4A protease activity, an NS3/4A peptide substrate was used. The substrate was RET S1 (Resonance Energy Transfer Depsipeptide Substrate; AnaSpec, Inc. cat #22991)(FRET peptide), described by Taliani et al. in Anal. Biochem. 240(2):60-67 (1996). The sequence of this peptide is loosely based on the NS4A/NS4B natural cleavage site for the HCV NS3 protease except there is an ester linkage rather than an amide bond at the cleavage site. The peptide also contains a fluorescence donor, EDANS, near one end of the peptide and an acceptor, DABCYL, near the other end. The fluorescence of the peptide is quenched by intermolecular resonance energy transfer (RET) between the donor and the acceptor, but as the NS3 protease cleaves the peptide the products are released from RET quenching and the fluorescence of the donor becomes apparent.

The peptide substrate was incubated with one of the three recombinant NS3/4A protease complexes, in the absence or presence of a compound of the present disclosure. The inhibitory effects of a compound were determined by monitoring the formation of fluorescent reaction product in real time using a Cytofluor Series 4000.

The reagents were as follow: HEPES and Glycerol (Ultrapure) were obtained from GIBCO-BRL. Dimethyl Sulfoxide (DMSO) was obtained from Sigma. β-Mercaptoethanol was obtained from Bio Rad.

Assay buffer: 50 mM HEPES, pH 7.5; 0.15 M NaCl; 0.1% Triton; 15% Glycerol; 10 mM βME. Substrate: 2 μM final concentration (from a 2 mM stock solution in DMSO stored at −20° C.). HCV NS3/4A protease type 1a (1b), 2-3 nM final concentration (from a 5 μM stock solution in 25 mM HEPES, pH 7.5, 20% glycerol, 300 mM NaCl, 0.2% Triton-X100, 10 mM βME). For compounds with potencies approaching the assay limit, the assay was made more sensitive by adding 50 μg/ml Bovine Serum Albumin (Sigma) to the assay buffer and reducing the end protease concentration to 300 pM.

The assay was performed in a 96-well polystyrene black plate from Falcon. Each well contained 25 μl NS3/4A protease complex in assay buffer, 50 μl of a compound of the present disclosure in 10% DMSO/assay buffer and 25 μl substrate in assay buffer. A control (no compound) was also prepared on the same assay plate. The enzyme complex was mixed with compound or control solution for 1 min before initiating the enzymatic reaction by the addition of substrate. The assay plate was read immediately using the Cytofluor Series 4000 (Perspective Biosystems). The instrument was set to read an emission of 340 nm and excitation of 490 nm at 25° C. Reactions were generally followed for approximately 15 min.

The percent inhibition was calculated with the following equation: 100−[(δF_(inh)/δF_(con))×100] where δF is the change in fluorescence over the linear range of the curve. A non-linear curve fit was applied to the inhibition-concentration data, and the 50% effective concentration (IC₅₀) was calculated by the use of Excel XLfit software using the equation, y=A+((B−A)/(1+((C/x)^D))).

Compounds of the present disclosure, which were tested against more than one type of NS3/4A complex, were found to have similar inhibitory properties though the compounds uniformly demonstrated greater potency against the 1b strains as compared to the 1a strains.

Specificity Assays

The specificity assays were performed to demonstrate the in vitro selectivity of the compounds of the present disclosure in inhibiting HCV NS3/4A protease complex as compared to other serine or cysteine proteases.

The specificities of compounds of the present disclosure were determined against a variety of serine proteases: human neutrophil elastase (FINE), porcine pancreatic elastase (PPE) and human pancreatic chymotrypsin and one cysteine protease: human liver cathepsin B. In all cases a 96-well plate format protocol using a fluorometric Amino-Methyl-Coumarin (AMC) substrate specific for each enzyme was used as described previously (PCT Patent Application No. WO 00/09543) with some modifications to the serine protease assays. All enzymes were purchased from Sigma, EMDbiosciences while the substrates were from Bachem, Sigma and EMDbiosciences.

Compound concentrations varied from 100 to 0.4 μM depending on their potency. The enzyme assays were each initiated by addition of substrate to enzyme-inhibitor pre-incubated for 10 min at room temperature and hydrolysis to 15% conversion as measured on cytofluor.

The final conditions for each assay were as follows:

-   50 mM Tris(hydroxymethyl)aminomethane hydrochloride (Tris-HCl) pH 8,     0.5 M Sodium Sulfate (Na₂SO₄), 50 mM NaCl, 0.1 mM EDTA, 3% DMSO,     0.01% Tween-20 with 5 μM LLVY-AMC and 1 nM Chymotrypsin. -   50 M Tris-HCl, pH 8.0, 50 mM NaCl, 0.1 mM EDTA, 3% DMSO, 0.02%     Tween-20, 5 μM succ-AAPV-AMC and 20 nM HNE or 8 nM PPE; -   100 mM NaOAC (Sodium Acetate) pH 5.5, 3% DMSO, 1 mM TCEP     (Tris(2-carboxyethyl)phosphine hydrochloride), 5 nM Cathepsin 13     (enzyme stock activated in buffer containing 20 mM TCEP before use),     and 2 μM Z-FR-AMC diluted in H₂O.

The percentage of inhibition was calculated using the formula: [1−(UV_(inh)−UV_(blank))/(UV_(clt)−UV_(blank)))]×100

A non-linear curve fit was applied to the inhibition-concentration data, and the 50% effective concentration (IC₅₀) was calculated by the use of Excel XLfit software.

Generation of HCV Replicon

An HCV replicon whole cell system was established as described by Lohmann V, Korner F, Koch J, Herian U, Theilmann L, Bartenschlager R., Science 285(5424):110-3 (1999). This system enabled us to evaluate the effects of our HCV Protease compounds on HCV RNA replication. Briefly, using the HCV strain 1b sequence described in the Lohmann paper (Assession number: AJ238799), an HCV cDNA was synthesized by Operon Technologies, Inc. (Alameda, Calif.), and the full-length replicon was then assembled in plasmid pGem9zf(+) (Promega, Madison, Wis.) using standard molecular biology techniques. The replicon consists of (i) the HCV 5′ UTR fused to the first 12 amino acids of the capsid protein, (ii) the neomycin phosphotransferase gene (neo), (iii) the IRES from encephalomyocarditis virus (EMCV), and (iv) HCV NS3 to NS5B genes and the HCV 3′ UTR. Plasmid DNAs were linearized with ScaI and RNA transcripts were synthesized in vitro using the T7 MegaScript transcription kit (Ambion, Austin, Tex.) according to manufacturer's directions. In vitro transcripts of the cDNA were transfected into the human hepatoma cell line, HUH-7. Selection for cells constitutively expressing the HCV replicon was achieved in the presence of the selectable marker, neomycin (G418). Resulting cell lines were characterized for positive and negative strand RNA production and protein production over time.

HCV Replicon FRET Assay

The HCV replicon FRET assay was developed to monitor the inhibitory effects of compounds described in the disclosure on HCV viral replication. HUH-7 cells, constitutively expressing the HCV replicon, were grown in Dulbecco's Modified Eagle Media (DMEM) (Gibco-BRL) containing 10% Fetal calf serum (FCS) (Sigma) and 1 mg/ml G418 (Gibco-BRL). Cells were seeded the night before (1.5×10⁴ cells/well) in 96-well tissue-culture sterile plates. Compound and no compound controls were prepared in DMEM containing 4% FCS, 1:100 Penicillin/Streptomysin (Gibco-BRL), 1:100 L-glutamine and 5% DMSO in the dilution plate (0.5% DMSO final concentration in the assay). Compound/DMSO mixes were added to the cells and incubated for 4 days at 37° C. After 4 days, cells were first assessed for cytotoxicity using alamar Blue (Trek Diagnotstic Systems) for a CC₅₀ reading. The toxicity of compound (CC₅₀) was determined by adding 1/10 volume of alamar Blue to the media incubating the cells. After 4 h, the fluorescence signal from each well was read, with an excitation wavelength at 530 nm and an emission wavelength of 580 nm, using the Cytofluor Series 4000 (Perspective Biosystems). Plates were then rinsed thoroughly with Phosphate-Buffered Saline (PBS) (3 times 150 μl). The cells were lysed with 25 μl of a lysis assay reagent containing an HCV protease substrate (5× cell Luciferase cell culture lysis reagent (Promega #E153A) diluted to 1× with distilled water, NaCl added to 150 mM final, the FRET peptide substrate (as described for the enzyme assay above) diluted to 10 μM final from a 2 mM stock in 100% DMSO. The plate was then placed into the Cytofluor 4000 instrument which had been set to 340 nm excitation/490 nm emission, automatic mode for 21 cycles and the plate read in a kinetic mode. EC₅₀ determinations were carried out as described for the IC₅₀ determinations.

HCV Replicon Luciferase Reporter Assay

As a secondary assay, EC₅₀ determinations from the replicon FRET assay were confirmed in a replicon luciferase reporter assay. Utilization of a replicon luciferase reporter assay was first described by Krieger et al (Krieger N, Lohmann V, and Bartenschlager R, J. Virol. 75(10):4614-4624 (2001)). The replicon construct described for our FRET assay was modified by inserting cDNA encoding a humanized form of the Renilla luciferase gene and a linker sequence fused directly to the 3′-end of the luciferase gene. This insert was introduced into the replicon construct using an Asc1 restriction site located in core, directly upstream of the neomycin marker gene. The adaptive mutation at position 1179 (serine to isoleucine) was also introduced (Blight K J, Kolykhalov, A A, Rice, C M, Science 290(5498):1972-1974). A stable cell line constitutively expressing this HCV replicon construct was generated as described above. The luciferase reporter assay was set up as described for the HCV replicon FRET assay with the following modifications. Following 4 days in a 37° C./5% CO₂ incubator, cells were analyzed for Renilla Luciferase activity using the Promega Dual-Glo Luciferase Assay System. Media (100 μl) was removed from each well containing cells. To the remaining 50 μl of media, 50 μl of Dual-Glo Luciferase Reagent was added, and plates rocked for 10 min to 2 h at room temperature. Dual-Glo Stop & Glo Reagent (50 μl) was then added to each well, and plates were rocked again for an additional 10 min to 2 h at room temperature. Plates were read on a Packard TopCount NXT using a luminescence program.

The percentage inhibition was calculated using the formula below:

${\%\mspace{14mu}{control}} = \frac{\begin{matrix} {{average}\mspace{14mu}{luciferase}\mspace{14mu}{signal}\mspace{14mu}{in}} \\ {{experimental}\mspace{14mu}{wells}\mspace{14mu}\left( {+ {compound}} \right)} \end{matrix}\mspace{14mu}}{\begin{matrix} {{average}\mspace{14mu}{luciferase}\mspace{14mu}{signal}\mspace{14mu}{in}} \\ {D\; M\; S\; O\mspace{14mu}{control}\mspace{14mu}{wells}\mspace{14mu}\left( {- {compound}} \right)} \end{matrix}\mspace{14mu}}$ The values were graphed and analyzed using XLfit to obtain the EC₅₀ value.

The compound of the current disclosure was tested and found to have the activity as follows: IC50: A=5 to 30 nM; B 31-100 nM; EC50: A=75-500 nM; B=501-1000 nM.

TABLE 2 Example Number IC50 EC50 1 5 nM 75 nM 2 A B 3 A B 4 B B

It will be evident to one skilled in the art that the present disclosure is not limited to the foregoing illustrative examples, and that it can be embodied in other specific forms without departing from the essential attributes thereof. It is therefore desired that the examples be considered in all respects as illustrative and not restrictive, reference being made to the appended claims, rather than to the foregoing examples, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. 

1. A compound of formula (I)

or a pharmaceutically acceptable salt thereof, wherein R¹ is selected from hydroxy and —NHSO₂R⁵; R² is selected from hydrogen, alkenyl, alkyl, and cycloalkyl, wherein the alkenyl, the alkyl, and the cycloalkyl are each optionally substituted with one, two, three, or four halo groups; R³ is a phenyl group substituted with an additional phenyl or a heterocyclyl wherein the additional phenyl and the heterocyclyl can be further optionally substituted with one, two, three, four, or five substituents independently selected from alkoxy, alkyl, cyano, halo, haloalkoxy, haloalkyl, and hydroxy; R⁴ is selected from hydrogen, alkoxycarbonyl, alkyl, alkylcarbonyl, alkylsulfonyl, cycloalkyloxycarbonyl, haloalkoxycarbonyl, haloalkyl, haloalkylcarbonyl, haloalkylsulfonyl, (NR^(a)R^(b))carbonyl, and (NR^(a)R^(b))sulfonyl, wherein the cycloalkyl part of the cycloalkyloxycarbonyl is optionally substituted with one, two, or three haloalkyl groups; R⁵ is selected from alkyl, aryl, arylalkyl, cycloalkyl, (cycloalkyl)alkyl, heterocyclyl, and —NR^(a)R^(b); wherein the alkyl and cycloalkyl are each optionally substituted with one group selected from alkyl, alkoxy, halo, haloalkyl, cyano, cyanoalkyl, and haloalkoxy; R^(a) and R^(b) are independently selected from hydrogen, alkoxy, alkyl, aryl, arylalkyl, cycloalkyl, (cycloalkyl)alkyl, haloalkyl, heterocyclyl, and heterocyclylalkyl; X is selected from O, S, SO, and SO₂; and Q is a C₅₋₉ saturated or unsaturated chain optionally substituted with one or two groups independently selected from alkyl, halo, and haloalkyl.
 2. A compound of claim 1, or a pharmaceutically acceptable salt thereof, wherein R¹ is —NHSO₂R⁵.
 3. A compound of claim 2, or a pharmaceutically acceptable salt thereof, wherein X is S.
 4. A compound of claim 3, or a pharmaceutically acceptable salt thereof, wherein Q is a C₇₋₉ saturated or unsaturated unsubstituted chain.
 5. A compound of claim 4, or a pharmaceutically acceptable salt thereof, wherein R³ is a phenyl group substituted with an unsubstituted phenyl group.
 6. A compound of claim 5, or a pharmaceutically acceptable salt thereof, wherein R² is alkenyl.
 7. A compound of claim 6, or a pharmaceutically acceptable salt thereof, wherein R⁴ is alkoxycarbonyl.
 8. A compound of claim 1, or a pharmaceutically acceptable salt thereof, wherein R¹ is —NHSO₂R⁵; R² is alkenyl; and R⁴ is alkoxycarbonyl.
 9. A compound of claim 1, or a pharmaceutically acceptable salt thereof, wherein R¹ is —NHSO₂R⁵; wherein R⁵ is cycloalkyl; R² is alkenyl; R³ is a phenyl group substituted with an unsubstituted phenyl group; R⁴ is alkoxycarbonyl; X is S; and Q is a C₇₋₉ saturated or unsaturated unsubstituted chain.
 10. A compound selected from

or a pharmaceutically acceptable salt thereof.
 11. A composition comprising the compound of claim 1, or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier.
 12. A method of treating an HCV infection in a patient, comprising administering to the patient a therapeutically effective amount of a compound of claim 1, or a pharmaceutically acceptable salt thereof.
 13. The method of claim 12 further comprising administering at least one additional compounds having anti-HCV activity prior to, after, or simultaneously with the compound of claim 1, or a pharmaceutically acceptable salt thereof.
 14. The method of claim 13 wherein at least one of the additional compounds is an interferon or a ribavirin.
 15. The method of claim 14 wherein the interferon is selected from interferon alpha 2B, pegylated interferon alpha, consensus interferon, interferon alpha 2A, and lymphoblastiod interferon tau.
 16. The method of claim 13 wherein at least one of the additional compounds is selected from interleukin 2, interleukin 6, interleukin 12, a compound that enhances the development of a type 1 helper T cell response, interfering RNA, anti-sense RNA, Imiqimod, ribavirin, an inosine 5′-monophospate dehydrogenase inhibitor, amantadine, and rimantadine.
 17. The method of claim 13 wherein at least one of the additional compounds is effective to inhibit the function of a target selected from HCV metalloprotease, HCV serine protease, HCV polymerase, HCV helicase, HCV NS4B protein, HCV entry, HCV assembly, HCV egress, HCV NS5A protein, and IMPDH for the treatment of an HCV infection. 